Currently there are two types of annular combustor turbines that are configured to enhance combustion by inducing one or more vortices of fuel particles entrained in air. One type of annular combustor turbine is a can annular combustor which consists of separate combustor chambers interconnected by conduit (interconnectors). Pressurized air from a compressor is directed into the chambers by creating a pressure drop within the chambers and by stators which remove the helical swirl of pressurized air exiting the compressor. This air is mixed with fuel particles and ignited by a single ignitor. Flame from the combustion of the gas and air mixture is propagated to the chambers via the conduits. A disadvantage of the can annular combustor is that the metal walls of the different chambers require a considerable amount of cooling.
The other type of annular turbine is a full annular combustor which aerodynamically maintains individual combustor chambers. The walls between the individual chambers are eliminated to reduce the weight of the combustor and the amount of air necessary to cool them. Each combustor chamber is aerodynamically formed by a swirler which is associated with a fuel injector. Air used for combustion is introduced into the combustion chamber through holes which are aligned with each chamber to insure proper air/fuel mixture. Flame generated by a single igniter propagates to all the chambers.
This type of combustor, however, has the disadvantage of losing some of the control of the combustion flame in each chamber when the power of the turbine is varied. This power is typically controlled by varying the speed of the compressor. Loss of flame control results from changing the swirling speed of the pressurized air introduced into the annular combustor. Since the stators used to remove the swirling component of the pressurized air are commonly positioned to properly direct pressurized air at full power, they fail to totally eliminate swirling components at different compressor speeds. Also, since the position of the holes are fixed, swirling components of the pressurized air are introduced into the individual chambers causing the ratio of the air/fuel mixture in each chamber to change. Changing the speed of compressor also changes the pressure drop necessary for introducing air for combustion. If the pressure drop needed for air to reach the center of the combustor is significantly reduced, the temperature of the core of the combustor increases.
A problem common to both of these annular combustor turbines includes introducing fuel particles of variable size. Larger sized particles experience the same residence time in these combustors as do smaller particles; this time, however, is often insufficient to completely combust the larger fuel particles except within the peak power range of the combustor. Efficiency outside this peak power range is noticeably decreased.
Cooling problems also exist for both combustors when the pressures of the combustors are increased to improve efficiency. Since increases in pressure result in hotter flames, temperatures of 4000.degree. F. or more could develop which would melt the walls of the chambers if they are not sufficiently cooled. Typically, the outer surfaces of the combustor is cooled with air circulating around the combustor before it is introduced into the combustor. For most combustors, cooling steps are provided which introduce air in a direction parallel to the interior surface of the combustor to induce a blanket of air which insulates the interior surface from the combustion gas. Often, however, this air is used for cooling and not combustion which causes a poor combustion exit temperature distribution. As a result, additional cooling is required for cooling the turbine.